1. Field of the Invention
The present invention relates to a so-called hybrid type operating apparatus provided in a working industrial vehicle.
2. Description of the Related Art
An example of a operating apparatus for an industrial vehicle of this type is disclosed in JP 2005-298163 A. According to the first embodiment of JP2005-298163A (see FIG. 1), there is disclosed a cargo handling apparatus for a cargo handling industrial vehicle having an engine, a generator motor, a clutch for connecting and disconnecting power between the engine and the generator motor, an electricity storage means, a cargo handling means (load to be driven), and a cargo handling load detecting means for detecting resistance load. The generator motor is set to either a generator mode in which a driving force of the engine is transmitted to the generator motor through the clutch to generate power and store the power in the electricity storage means, or an electric motor mode in which the generator motor is supplied with driving power from the electricity storage means to function as an electric motor.
In the above construction, when the load detected by the cargo handling load detecting means is small, the clutch is set to a disconnected state to stop or idle the engine, and the cargo handling means is driven by the generator motor in the electric motor mode to perform cargo handling operations. When, during the cargo handling operation, the cargo handling load detecting means detects an increase in load in excess of a predetermined value, an increase in engine RPM is started while increasing an output of the generator motor in the electric motor mode. When the engine RPM becomes equal to the RPM of the generator motor, the clutch is set to a connected state, and the driving force of the engine is transmitted to the cargo handling means to perform cargo handling operations.
Further, according to the first embodiment of JP 2005-298163 A, the engine is started through cranking by the generator motor in the electric motor mode with the clutch in the connected state.
According to the third embodiment of JP 2005-298163 A (see FIG. 3), there is disclosed a construction in which the engine and the generator motor are connected to each other through the intermediation of a one-way clutch instead of the above-mentioned clutch. With this construction, when, during cargo handling operations, the cargo handling load detecting means detects an increase in load in excess of a predetermined value, an increase in the engine RPM is started while increasing the output of the generator motor in the electric motor mode. When the engine RPM becomes equal to the RPM of the generator motor, the one-way clutch is automatically connected, and the driving force of the engine is transmitted to the cargo handling means.
With this construction, there is no need to perform the clutch connection/disconnection control (inclusive of control for monitoring to check whether the engine RPM has become equal to the RPM of the generatormotor) required in the first embodiment described above, thereby achieving a simplification in electrical construction.
However, with the construction of the third embodiment of JP 2005-298163 A, it is impossible to drive the engine by the generator motor because the one-way clutch is then set to the disconnected state. Thus, to start the engine, it is necessary to provide a dedicated starter motor, which means there is some room left for improvement (see the second and third sentences of paragraph [0063] of JP 2005-298163 A).